The U.S. document that begins with "We the People" is the Constitution. Adopted in 1787, it established the framework of the federal government and delineated the rights of the citizens. The phrase signifies that the authority and power of the government are derived from the people, reflecting the democratic principles upon which the nation was founded. The Constitution has undergone multiple amendments and remains a living document that guides American law and governance today, embodying the democratic ideals that continue to shape the United States.